The general field of this invention relates to thermoplastic compositions containing a volatile component for release into the atmosphere. Such compositions are known, and are described in U.S. Pat. Nos. 3,725,311, 3,926,655, 4,051,159, 4,095,031, and 4,184,099. As disclosed in the cited patents, the volatile component may be an odor-neutralizing substance or, more commonly, a volatile perfume oil. The thermoplastic resins disclosed for this purpose include a terpolymer of vinyl chloride, vinyl acetate, and vinyl alcohol, which may be used in admixture with a copolymer of vinyl chloride and vinyl acetate, plasticized or unplasticized polyamide resins, copolymers of vinyl acetate and ethyl acrylate, etc. The prior art also discloses that such volatile component-releasing thermoplastic compositions may be formed in various shapes such as by molding or extruding. The cited United States Patents do not specifically describe the insertion of such thermoplastic compositions in frames defining the shape and providing support for the formed resins. However, in the published South African Specification No. 770,610, a stained glass mobile is described which is formed from a metal frame and a hydrophilic thermosetting resin composition containing a perfume oil (see Example IX). In general, the prior art has failed to disclose a satisfactory manufacturing procedure for such products.
In manufacturing perfume-release plastic decorations which resemble stained glass miniatures it is important that the products have an attractive appearance as initially manufactured and that this attractive appearance is maintained during the normal period of use. One problem associated with the manufacture of products having these characteristics is that the perfume component, the volatile perfume oil, must form a substantial part of the composition for effective immediate and sustained release. For example, the compositions may contain from 5 to 25% by weight, or more, of the perfume oil. As the perfume oil evaporates, the compositions tend to shrink or distort. Such shrinkage tends to cause the compositions to separate from enclosing frames. Over the normal period of use of the decorations, which may extend for a number of weeks, the sections of resin composition which are initially secured within the openings of a frame can separate entirely and fall out of the frame. Even before this occurs, however, the partial separation of the resin section from the frame can seriously detract from the appearance of the product.
Another problem relating to the manufacture of products of the character described is that the resin compositions are most attractive when they are prepared in various clear colors. However, it is difficult to manufacture the products with the desired degree of transparency and clarity. In particular, where the resin compositions are heated to a flowable condition for filling the openings of the frame, the bottom surface tends to reproduce the slight irregularities of the supporting surface on which the product is being manufactured, such as, for example, the surface of a Teflon-coated steel plate. When such products are suspended in front of a light source, such as a window, the resin sections may appear clouded or marred.